Industrial operations typically emit large quantities of pollutants such as CO and VOCs. Vehicles, aircrafts, waste water treatment plants, light manufacturing facilities, certain small businesses (e.g., dry cleaners, bakeries, restaurants, etc.), and homes also emit CO and VOCs, albeit typically in much smaller quantities compared to industrial operations.
CO is known for its toxicity to humans and animals due to its high affinity to hemoglobin, which reduces the effectiveness of oxygen transportation in blood even at a concentration level of a hundred ppm. VOCs cause several health and environmental problems and are also precursors of ground-level ozone, which contributes to smog formation. The overall chemistry is a complex interaction between VOCs, NOx and ozone which results in the formation of photochemical smog. Conventional technologies such as themocatalytic oxidation are usually found to be expensive to implement and have a tendency to result in secondary pollution at low temperatures.
The emission control of VOCs and CO at temperatures ranging from about 20° C. to about 50° C. has become increasingly important for public health, government regulation, and business development. For example, formaldehyde which is a major indoor air pollutant has been listed recently as a carcinogen. Currently known technologies for VOCs and CO abatement at low temperatures, especially at about room temperature, include photocatalysis, high voltage discharge, sorbents, and oxidation catalysts.
However, none of the currently known methods appear to achieve removal of VOCs and/or CO at temperatures ranging from about 20° C.-50° C. by complete oxidation.
From a practical application point of view, removal of VOCs and/or CO at temperatures ranging from about 20° C. to about 50° C. by complete oxidation has significant advantages over other known methods due to its low consumption of energy and raw materials, low production cost, and high selectivity.
There is a need to develop more active oxidation catalysts that allow the complete oxidation of CO and the VOCs at room temperature with sufficient stability and durability.